What medications are available to treat allergies?

Allergy medications are available as pills, liquids, inhalers, nasal sprays, eye drops, skin creams and shots (injections). Some allergy medications are available over-the-counter, while others are available by prescription only. Here's a summary of the various types of allergy medications and why they're used.

Corticosteroids

Corticosteroids help prevent the release of symptom-causing chemicals during an allergic reaction. Most corticosteroid medications require a prescription.

Inhaled corticosteroids are used to relieve symptoms triggered by airborne allergy-triggering substances (allergens). These medications are generally taken on a daily basis as part of asthma treatment. Examples include fluticasone (Flovent Diskus, Flovent HFA), budesonide (Pulmicort Flexhaler), mometasone (Asmanex Twisthaler), beclomethasone (Qvar) and ciclesonide (Alvesco). Side effects are generally minor and can include mouth and throat irritation and oral yeast infections.

Corticosteroid skin creams relieve allergic skin reactions such as scaling and itching. Some low-potency corticosteroid creams are available without a prescription, but talk to your doctor before using a topical corticosteroid for more than a few weeks. Examples include hydrocortisone (Cortaid, others) and triamcinolone (Kenalog, others). Side effects can include skin irritation and discoloration. Long-term use, especially of stronger prescription corticosteroids, thins the top layer of the skin, resulting in easy bruising where the cream has been applied. Corticosteroids are available in liquid form that can be useful for skin conditions involving the scalp.

Oral corticosteroids (pills and liquids) are used to treat severe symptoms caused by all types of allergic reactions. Examples include prednisone (Prednisone Intensol) and prednisolone (Prelone, others). Because they can cause numerous short- and long-term side effects, oral corticosteroids are usually prescribed for short periods of time. Long-term use can cause cataracts, osteoporosis, muscle weakness, stomach ulcers and delayed growth in children. Oral corticosteroids can also worsen hypertension. In some situations, corticosteroids may be given as a shot (injection) rather than pills.

Antihistamines

Antihistamines block histamine, a symptom-causing chemical released by your immune system during an allergic reaction.

Oral antihistamines (pills and liquids) ease symptoms such as swelling, runny nose, itchy or watery eyes, and hives (urticaria). Over-the-counter oral antihistamines include loratadine (Claritin) and cetirizine (Zyrtec). Desloratadine (Clarinex) and levocetirizine (Xyzal) are available by prescription. Fexofenadine (Allegra) is available both over-the-counter and by prescription. Some oral antihistamines may cause dry mouth and drowsiness. Older antihistamines such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton) and clemastine (Tavist) are more likely to cause drowsiness and slow your reaction time. These sedating antihistamines shouldn't be taken when driving or doing other potentially dangerous activities.

Antihistamine eye drops are often combined with other medications such as mast cell stabilizers or decongestants. Antihistamine eyedrops can ease symptoms such as itching, redness and swollen eyes. You may need to use these medications several times a day, because the effects may last only a few hours. Over-the-counter examples include ketotifen (Zaditor, Alaway, others) and pheniramine (Visine-A, Opcon-A, others). Prescription examples include emedastine (Emadine) and olopatadine (Patanol, others). Side effects of these medications can include red eyes, watery eyes, mild stinging or burning and headache. Antihistamine eyedrops increase the risk of eye inflammation when you're wearing contact lenses.

Decongestants

Decongestants are used for quick, temporary relief of nasal and sinus congestion. You may need to avoid decongestants if you're pregnant, if you're an older adult or if you have high blood pressure. Check with your doctor to see which medications are safe for you.

Oral decongestants (pills and liquids) relieve nasal and sinus congestion caused by hay fever. Many decongestants are available over-the-counter. A common example is pseudoephedrine (Sudafed, others). A number of medications contain a decongestant such as pseudoephedrine combined with other medications. Claritin-D, for example, contains pseudoephedrine and an antihistamine. Oral decongestants can cause a number of side effects, including irritability, fast or irregular heartbeat, dizziness, insomnia, headaches, anxiety, tremors, and increased blood pressure.

Nasal decongestant sprays and drops relieve nasal and sinus congestion. Examples include phenylephrine (Neo-Synephrine, others) and oxymetazoline (Afrin, others). Nasal decongestants can cause dryness, burning or stinging inside the nose, runny nose, and sneezing. Taking too much of a nasal decongestant can cause irritability, fast or irregular heartbeat, dizziness, insomnia, headaches, anxiety, tremors, and increased blood pressure. Don't use a decongestant nasal spray for more than a week or so, or you may develop severe congestion as soon as you stop taking it (rebound congestion).

Other allergy medications

A few other medications work by blocking symptom-causing chemicals released during an allergic reaction.

Montelukast (Singulair) is a prescription medication that blocks symptom-causing chemicals called leukotrienes. This oral medication relieves allergy signs and symptoms including nasal congestion, runny nose and sneezing. Side effects can include upper respiratory infection in adults, and headache, ear infection and sore throat in children. The Food and Drug Administration (FDA) has warned that in some people, leukotriene-blocking medications could possibly cause psychological symptoms, such as irritability, anxiousness, insomnia, hallucinations, aggression, depression, and suicidal thinking or behavior.

Cromolyn (Nasalcrom) is an over-the-counter nasal spray. It prevents the release of histamine and other symptom-causing chemicals during an allergic reaction. This medication works best when you take it before your symptoms start. Some people need to use the spray three or four times a day. Side effects may include nasal stinging or sneezing.

Immunotherapy

Immunotherapy injections (allergy shots) may relieve hay fever symptoms or allergic asthma that doesn't improve with medications. Injections may also be an option if you aren't able to take oral allergy medications without having side effects. Over a period of three to five years, you receive regular injections containing allergen extracts. The goal is to stop your body from reacting to specific allergens and decrease or eliminate your need for medications. Immunotherapy may be especially effective if you're allergic to cat dander, dust mites, or pollen produced by trees, grass or weeds. In children with allergic rhinitis, immunotherapy may help prevent the development of asthma. Rarely, immunotherapy injections can cause a life-threatening allergic reaction (anaphylaxis).

Emergency epinephrine shots

Epinephrine shots are used to stop a severe allergic reaction. These self-injecting syringe and needle (autoinjector) devices include Twinject, EpiPen and EpiPen Jr. You may need to carry an autoinjector if you're likely to have a severe allergic reaction to a certain food, such as peanuts, or if you're allergic to bee or wasp venom. A severe allergic reaction can cause anaphylaxis — a sudden, life-threatening reaction. Epinephrine is a form of adrenaline that can help slow the reaction while you seek emergency treatment.

If you do carry an emergency epinephrine shot, replace it by the expiration date or it may not work correctly.

Get your doctor's advice

Work with your doctor to help you avoid problems and choose the most effective allergy medications. Even over-the-counter allergy medications have side effects, and some allergy medications can cause problems when combined with other medications.

It's especially important to talk to your doctor about taking allergy medications if:

You're pregnant or breast-feeding a child.

You have a chronic health condition such as diabetes, glaucoma, osteoporosis or high blood pressure.

You're taking any other medications, including herbal supplements.

You're treating allergies in a child. Children need different doses of medication or different medications than adults. Some medications, such as corticosteroids, can cause side effects in children.

You're treating allergies in an older adult. Some allergy medications can cause confusion, urinary symptoms or other side effects in older adults.

You're already taking an allergy medication that isn't working. Bring the medication with you in its original bottle when you see your doctor.

Keep track of your symptoms, when you use your medications, and how much you use — that way you and your doctor can figure out what works best. You may need to try a few different medications to determine which ones are most effective and have the least bothersome side effects for you.

Forty years ago, one of the greatest boxing matches in history took place in an unlikely setting: the capital of the Philippines. Muhammad Ali's epic win over great rival Joe Frazier in 1975 became known as the "Thrilla in Manila."